What is bone remodeling?
Bone remodeling is a continuous process of bone absorption and formation in order to maintain normal bone quality. Normal bone mass means healthy bones are strong and free of problems such as osteoporosis. As long as the person is alive, this process will take place in the body. The cell that plays an important role is osteoclast, which is responsible for bone resorption. Osteoblasts are essential for the formation of bones; and osteoblasts, which signal that bones are compressed or injured. Constant remodeling enables bones to perform many of their functions, including structural support to the entire body and important calcium storage sites. Through skeletal remodeling, the body is also able to repair small fractures that occur during daily physical activity. During the reconstruction cycle, the old bones will be replaced by the new bones. In adults, this happens at a rate of about 10% per year. This is a natural process to ensure that normal bone mass is maintained with age. The remodeling cycle usually begins when bone damage or mechanical stress occurs. Growth hormone stimulates the production of osteoclasts, which then release enzymes that can dissolve the bone matrix, thereby forming pits on the surface of most bones. They live for about two weeks and then die naturally through programmed cell death or apoptotic processes.
Bone Remodeling Molecules Proteins
Osteoblasts are also stimulated by growth hormone. They are responsible for filling the pits formed by osteoclasts on the bone surface. As the bone matrix thickens, osteoblasts incorporate minerals such as calcium and phosphorus into the bone in a process called mineralization. After about three months of life, most mature into bone cells, which are mainly present in the bone matrix and signal mechanical stress and growth hormone damage. Other osteoblasts become lining cells on the bone surface and are responsible for releasing calcium into the bloodstream, while other osteoblasts die naturally. Osteoclasts, osteoblasts and osteocytes act within the receptor to regulate hormones and hormones. These include vitamin D, parathyroid hormone (PTH), calcitonin, testosterone and estrogen. Any disturbance of these chemicals can lead to certain medical conditions. For example, some studies have shown that estrogen deficiency in menopausal women causes delayed cell death in most osteoclasts, leaving bones exposed to their enzymatic action for longer periods and promoting osteoporosis.
Estrogen is a substance that promotes the development of secondary sexual characteristics and the maturation of sexual organs in female animals. It is produced by the ovaries and placenta of female animals. The receptors for estrogen are distributed in the uterus, vagina, breast, pelvis, and skin, bladder, urethra, bones and brain. Therefore, estrogen has a wide range of important physiological functions, not only promoting and maintaining female reproductive organs and secondary sexual characteristics Physiological effects, and have significant effects on endocrine, cardiovascular, metabolic systems, bone growth and maturity, and skin. Natural estrogens are mainly estradiol.
Parathyroid hormone (PTH)
Parathyroid hormone (PTH) is a basic single-chain polypeptide hormone secreted by parathyroid main cells. Its main function is to regulate the metabolism of calcium and phosphorus in vertebrates, which promotes the increase of blood calcium levels and the decrease of blood phosphorus levels. PTH promotes the increase of plasma calcium ion concentration, and its main target organs are bone and kidney. It mobilizes bone calcium into the blood, promotes the reabsorption of calcium ions and excretion of phosphate by the renal tubules, increases the blood calcium concentration and decreases the blood phosphorus concentration. In addition, PTH also indirectly promotes intestinal absorption of calcium ions. The secretion of PTH is mainly regulated by the plasma calcium ion concentration. Increased plasma calcium ion concentration inhibits PTH secretion; decreased plasma calcium ion concentration stimulates PTH secretion.
Testosterone is a male hormone, its role is to stimulate male sexual desire, promote the growth of facial hair and the formation of male signs. Generally speaking, people are afraid of increased risk of heart disease and prostate cancer after increasing testosterone levels. But research in recent years has confirmed that low levels of testosterone are common in men with angina and that it is a danger in itself.
Vitamin D is a fat-soluble vitamin, which is a cyclopentane polyhydrophenanthrene compound. It is a group of vitamins that are structurally related to sterols and can prevent rickets. The most important are vitamins D3 and D2. The former is made from 7-dehydrocholesterol under the skin of human beings by ultraviolet irradiation. The latter is made of ergosterol contained in plants or yeasts by ultraviolet irradiation. The main function of vitamin D is to promote the absorption of calcium and phosphorus by small intestinal mucosal cells. Calcium absorption in the intestine requires a calcium-binding protein. 1,25-dihydroxyvitamin D3 can induce the synthesis of this protein, promote the absorption of Ca2+, and promote the regeneration of calcium salts and new bone formation. Re-absorption of calcium and phosphorus, so it can increase blood calcium and blood phosphorus concentration, which is beneficial to new bone formation and calcification.